A multichannel metering system of this type has become known from EP-B 302,752. In the prior-art metering system, a plurality of infusion containers acting as fluid flow sources are fastened to a chassis. These flow sources are connected to individual discharge lines, through which the substances or fluid flows to be metered reach a collection line, in which the individual fluid flows unite. A flow-adjusting means, with which each fluid flow can be individually influenced, is located in the line path of each discharge line. The flow-adjusting means are connected to a central, programmable control device, which is located in the lower part of the chassis, and which permits the selective actuation of the individual flow-adjusting means. The control device has a means for storing information, in which data fields on discharge schedules of the individual types of fluids are stored. The data fields can be polled in the form of menu screens to an operating surface, which has as the output means a "touch screen" for displaying the individual menu screens or menu masks, and has a "light pen" as an input means, with which individual menu functions can be activated via the touch screen. The individual flow-adjusting means for the fluid flows can be set to select metering rates by means of the menu screens, on the one hand, and, on the other hand, it is possible to specify information on the compatibility of individual types of fluids, and it is possible, via a keyboard menu screen, to read alphanumeric data, e.g., general patient data or metering rates, into the control device.
The prior-art metering system is highly complex in terms of operation, because defined menu screens must be polled one after another to perform defined control and monitoring functions, observing an operation hierarchy. A spontaneous, direct access to the data field of a defined fluid flow is not possible.
DE-A 33,29,977 discloses a four-channel metering system, in which the metering rates of the individual fluid flows are monitored by a central control device, but an individual coding switch, with which the metering rate can be set manually, is associated with each fluid flow source. All coding switches are connected to the control device, which calculates a total rate of delivery from the individual metering rates delivered by the coding switches to the control device, and displays it via a display on the control device.
The disadvantage of the prior-art metering system is the fact that corresponding coding switches must be provided for the individual metering rates at each fluid flow source because of the decentralized data input, as a result of which the coding switches may be located in a field of view that is unfavorable for the user, and there is a great risk of incorrect setting.